Visual or touchscreen password entry

ABSTRACT

A method of authenticating a user of a computing device is proposed, together with computing device on which the method is implemented. In the method a modified base image is overlaid with a modified overlay image on a display and movement of either the modified base image or modified overlay image is permitted if a criterion for movement is met. Positive authentication is indicated in response to the base image reference point on the modified base image being aligned with the overlay image reference point on the modified overlay image.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is related to commonly owned U.S. applicationSer. No. ______ entitled “ADJUSTING THE POSITION OF AN ENDPOINTREFERENCE FOR INCREASING SECURITY DURING DEVICE LOG-ON” having attorneydocket number 42783-1616; “PRESSURE-SENSITIVE MULTI-LAYER PASSWORDS”having attorney docket number 42783-2118; “OBSCURING VISUAL LOGIN”having attorney docket number 42783-2120; “MULTI-LAYERORIENTATION-CHANGING PASSWORDS” having attorney docket number42783-2259; “MULTI-LAYER MULTI-POINT OR PATHWAY-BASED PASSWORDS” havingattorney docket number 42783-2261; “MULTI-LAYERED COLOR-SENSITIVEPASSWORDS” having attorney docket number 42783-2263; “SIMPLE ALGEBRAICAND MULTI-LAYER PASSWORDS” having attorney docket number 42783-2265;“MULTI-LAYER MULTI-POINT OR RANDOMIZED PASSWORDS” having attorney docketnumber 42783-2267; “PASSWORD ENTRY USING 3D IMAGE WITH SPATIALALIGNMENT” having attorney docket number 42783-2269; and “PASSWORD ENTRYUSING MOVING IMAGES” having attorney docket number 42783-2271; all ofwhich were filed on the same date as this application and areincorporated herein.

TECHNICAL FIELD

The present disclosure relates generally to graphical authentication.

BACKGROUND

Passwords may be used in many situations where a user needs to beauthenticated. Situations requiring authentication may include theability to access or use a computer, mobile phone, PDA, or any otherdevice. They may also enable access to a physical location, or allow useof a credit/debit card or similar instrument. Passwords are typicallyalpha-numeric strings or sequences entered on a keyboard. Graphicalauthentication systems, where passwords are comprised of graphicalcomponents, also exist.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating a communication system includinga mobile communication device in which example embodiments of thepresent disclosure can be applied;

FIG. 2 is a block diagram illustrating a mobile communication device inaccordance with one example embodiment of the present disclosure;

FIG. 3 is a block diagram illustrating an authentication module inaccordance with one example embodiment of the present disclosure;

FIGS. 4 a and 4 b are flowcharts illustrating a method in accordancewith one example embodiment of the present disclosure;

FIG. 5 is a block diagram illustrating a computing device in accordancewith one example embodiment of the present disclosure;

FIG. 6 is a block diagram illustrating a computing device in accordancewith one example embodiment of the present disclosure; and

FIGS. 7 a to 7 d are screen shots illustrating one example embodiment ofthe present disclosure.

Like reference numerals are used in the drawings to denote like elementsand features.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

With existing graphical authentication systems, “shoulder surfing” canoccur. For example, a third party observer may be able to determinewhere a cursor is located at the end of the authentication process. Insome situations, a third party observer may observe where the user'sfingers are pointing. In other situations, a computer algorithm could beused to determine a pattern of where certain points on the overlay imageare located at the end of the authentication process.

The present application proposes a method for authenticating a user of acomputing device in which a criterion for moving either the base imageor the overlay image of a graphical authentication must be met.

In one aspect, there is provided one or more computer readable mediahaving computer readable instructions stored thereon that when executedby a processor implement a method of authenticating a user of acomputing device, the computing device having a memory storing a baseimage and an overlay image, the base image having a pre-selected baseimage reference point, and the overlay image having a pre-selectedoverlay image reference point, the method comprising: generating amodified base image; generating a modified overlay image; displaying, ona touch screen display, the modified base image overlaid by the modifiedoverlay image; receiving an input for moving one of the modified baseimage and the modified overlay image; moving the one of the modifiedbase image and the modified overlay image if a criterion for movement ofthe one of the modified base image and the modified overlay image ismet; and in response to alignment of the base image reference point onthe modified base image with the overlay image reference point on themodified overlay image at a point on the touch screen after the moving,indicating positive authentication.

In another aspect, there is provided a method of authenticating a userof a computing device, the computing device having a memory storing abase image and an overlay image, the base image having a pre-selectedbase image reference point, and the overlay image having a pre-selectedoverlay image reference point, the method comprising: generating amodified base image; generating a modified overlay image; displaying, ona touch screen display, the modified base image overlaid by the modifiedoverlay image; receiving an input for moving one of the modified baseimage and the modified overlay image; moving the one of the modifiedbase image and the modified overlay image if a criterion for movement ofthe one of the modified base image and the modified overlay image ismet; and in response to alignment of the base image reference point onthe modified base image with the overlay image reference point on themodified overlay image at a point on the touch screen after the moving,indicating positive authentication.

In another aspect, there is provided a computing device comprising: aprocessor; a touch screen; and one or more computer readable mediahaving computer readable instructions stored thereon that when executedby the processor implement a method of authenticating a user of thecomputing device, the computing device having a memory storing a baseimage and an overlay image, the base image having a pre-selected baseimage reference point, and the overlay image having a pre-selectedoverlay image reference point, the method including generating amodified base image; generating a modified overlay image; displaying, onthe touch screen, the modified base image overlaid by the modifiedoverlay image; receiving an input for moving one of the modified baseimage and the modified overlay image; moving the one of the modifiedbase image and the modified overlay image if a criterion for movement ofthe one of the modified base image and the modified overlay image ismet; and in response to alignment of the base image reference point onthe modified base image with the overlay image reference point on themodified overlay image at a point on the touch screen after the moving,indicating positive authentication.

In another aspect, there is provided one or more computer readable mediahaving computer readable instructions stored thereon that when executedby a processor implement a method of authenticating a user of acomputing device, the computing device having a memory storing a baseimage and an overlay image, the base image having a pre-selected baseimage reference point, and the overlay image having a pre-selectedoverlay image reference point, the method comprising: generating amodified base image; generating a modified overlay image; displaying, ona display, the modified base image overlaid by the modified overlayimage, wherein at least one of the modified base image and the modifiedoverlay image is display upon receiving a user input; receiving an inputfor moving one of the modified base image and the modified overlayimage; moving the one of the modified base image and the modifiedoverlay image; and in response to alignment of the base image referencepoint on the modified base image with the overlay image reference pointon the modified overlay image at a point on display after the moving,indicating positive authentication.

In some embodiments, the display is a touch screen and the user input isa touch anywhere on the screen. For example, the overlay image could bedisplayed upon touch. In other embodiments, the user input is a press ofa key or a click of a mouse.

In some embodiments, one or both of the modified overlay image and themodified base image is generated receiving a use input.

There are several ways to prevent or discourage the user from directlytouching the pre-selected reference point on either the overlay image orthe base image. The embodiments that follow are described as applied tothe overlay image or the base image. It is to be understood that theseembodiments can be equally applied to the other of the overlay image orthe base image or both the overlay and the base image, where feasible.

One non-limiting example includes only rendering the overlay image upondetecting a touch on the display. This feature prevents the user fromtouching his overlay reference point first and then moving the overlayimage. In some embodiments, the overlay image is rendered in a mannersuch that the pre-selected overlay reference point is not at the pointon the display touched by the user. Subsequent movement of the user'stouch moves the overlay image and positive authentication will beindicated once the overlay reference point is aligned with the baseimage reference point. In cases where the base image is moved, the baseimage can also be rendered in a manner such that the base-imagereference point does not appear at the point of the user's touch.Rendering the respective image in a manner such that the reference pointis not under the touch reduces the likelihood that a third partyobserver could determine the user's reference point because to determinethe overlay reference point in this embodiment, the third party observermust figure out which reference point never appears under the user'stouch.

Another way to prevent or discourage touching a pre-selected referencepoint on one image is to use the movement of the user's touch to movethe other image. For example, if the authentication system recognizesthat the user selected his overlay reference point, the system willallow the movement of the base image rather than the overlay image inresponse to movement of the user's touch. The user then must move thebase image such that the base image reference point aligns with theoverlay reference point. Likewise, if the user touches the base imagereference point, movement of the user's touch will result in the overlayimage moving. In other embodiments, which image moves in response tomovement of the user's touch randomly alternates upon eachauthentication attempt.

In another embodiment, a dedicated point on the overlay image must betouched in order to move the overlay image. In a non-limiting example, a“tab’ or “pull” is provided on the display that must be used to move theoverlay image. In some embodiments, multiple dedicated points or tabsare provided so the user is not always moving the grid in the samedirection. In some embodiments, the dedicated point changes locations oneach log-in. In some embodiments, a dedicated navigation area isprovided on the display. The user must touch within this dedicatednavigation area in order to move the overlay image. Non-limitingexamples of a dedicated navigation area are a blank square, such as avirtual touch pad, or an area at the center of a touch screen.

Another way to discourage the user from touching the overlay referencepoint directly is to randomize the overlay image upon detecting a touch.For example, in the case of a number grid overlay image, as soon as thegrid is selected to be moved, the entire grid is randomized. Of course,the overlay image is not limited to numbers and non-limiting examples ofother types of reference points that can appear in the overlay imageinclude shapes, icons, and faces.

In some embodiments a touch is distinguished from a stroking movementand the overlay image is randomized upon a touch but will remain stablefor stroking movements. A stroke may be distinguished from a touch byits repetitive nature within a set tolerance. For example in someembodiments, a vector stroke within a maximum distance of a start pointwill not result in randomization of the overlay image. In someembodiments, there is time element to the tolerance. For example, if thetime between touches is greater than a time tolerance level, it will beassumed that the next touch is a new start point and not part of astroke pattern.

In another embodiment, the overlay image will only move if the usertouches somewhere other than the overlay image reference point. Forexample, if the user picks their number when selecting the referencepoint on a numbered grid, nothing happens, i.e., the grid will not move.This discourages the user from touching their reference point. Inanother embodiment, the overlay image can not be moved if the usertouches on any of the elements of the overlay image. In other words, inorder to move the overlay image, the user must touch between elements oron the edge of the overlay image. For example, in the case of a grid,the user may be required to touch on a grid line in order to move thegrid.

Embodiments of the present application are not limited to any particularoperating system, mobile device architecture, server architecture, orcomputer programming language.

Reference is first made to FIG. 1 which shows in block diagram form acommunication system 100 in which example embodiments of the presentdisclosure can be applied. The communication system 100 comprises anumber of mobile communication devices (mobile devices) 201 which may beconnected to the remainder of system 100 in any of several differentways. Accordingly, several instances of mobile communication devices 201are depicted in FIG. 1 employing different example ways of connecting tosystem 100. Mobile communication devices 201 are connected to a wirelesscommunication network 101 which may comprise one or more of a WirelessWide Area Network (WWAN) 102 and a Wireless Local Area Network (WLAN)104 or other suitable network arrangements. In some embodiments, themobile communication devices 201 are configured to communicate over boththe WWAN 102 and WLAN 104, and to roam between these networks. In someembodiments, the wireless network 101 may comprise multiple WWANs 102and WLANs 104.

The WWAN 102 may be implemented as any suitable wireless access networktechnology. By way of example, but not limitation, the WWAN 102 may beimplemented as a wireless network that includes a number of transceiverbase stations 108 (one of which is shown in FIG. 1) where each of thebase stations 108 provides wireless Radio Frequency (RF) coverage to acorresponding area or cell. The WWAN 102 is typically operated by amobile network service provider that provides subscription packages tousers of the mobile communication devices 201. In some embodiments, theWWAN 102 conforms to one or more of the following wireless networktypes: Mobitex Radio Network, DataTAC, GSM (Global System for MobileCommunication), GPRS (General Packet Radio System), TDMA (Time DivisionMultiple Access), CDMA (Code Division Multiple Access), CDPD (CellularDigital Packet Data), iDEN (integrated Digital Enhanced Network), EvDO(Evolution-Data Optimized) CDMA2000, EDGE (Enhanced Data rates for GSMEvolution), UMTS (Universal Mobile Telecommunication Systems), HSDPA(High-Speed Downlink Packet Access), IEEE 802.16e (also referred to asWorldwide Interoperability for Microwave Access or “WiMAX), or variousother networks. Although WWAN 102 is described as a “Wide-Area” network,that term is intended herein also to incorporate wireless MetropolitanArea Networks (WMAN) and other similar technologies for providingcoordinated service wirelessly over an area larger than that covered bytypical WLANs.

The WWAN 102 may further comprise a wireless network gateway 110 whichconnects the mobile communication devices 201 to transport facilities112, and through the transport facilities 112 to a wireless connectorsystem 120. Transport facilities may include one or more privatenetworks or lines, the public internet, a virtual private network, orany other suitable network. The wireless connector system 120 may beoperated, for example, by an organization or enterprise such as acorporation, university, or governmental department, which allows accessto a network 124 such as an internal or enterprise network and itsresources, or the wireless connector system 120, may be operated by amobile network provider. In some embodiments, the network 124 may berealised using the internet rather than an internal or enterprisenetwork.

The wireless network gateway 110 provides an interface between thewireless connector system 120 and the WWAN 102, which facilitatescommunication between the mobile communication devices 201 and otherdevices (not shown) connected, directly or indirectly, to the WWAN 102.Accordingly, communications sent via the mobile communication devices201 are transported via the WWAN 102 and the wireless network gateway110 through transport facilities 112 to the wireless connector system120. Communications sent from the wireless connector system 120 arereceived by the wireless network gateway 110 and transported via theWWAN 102 to the mobile communication devices 201.

The WLAN 104 comprises a wireless network which, in some embodiments,conforms to IEEE 802.11x standards (sometimes referred to as Wi-Fi) suchas, for example, the IEEE 802.11a, 802.11b and/or 802.11g standard.Other communication protocols may be used for the WLAN 104 in otherembodiments such as, for example, IEEE 802.11n, IEEE 802.16e (alsoreferred to as Worldwide Interoperability for Microwave Access or“WiMAX”), or IEEE 802.20 (also referred to as Mobile Wireless BroadbandAccess). The WLAN 104 includes one or more wireless RF Access Points(AP) 114 (one of which is shown in FIG. 1) that collectively provide aWLAN coverage area.

The WLAN 104 may be a personal network of the user, an enterprisenetwork, or a hotspot offered by an internet service provider (ISP), amobile network provider, or a property owner in a public or semi-publicarea, for example. The access points 114 are connected to an accesspoint (AP) interface 116 which may connect to the wireless connectorsystem 120 directly (for example, if the access point 114 is part of anenterprise WLAN 104 in which the wireless connector system 120 resides),or indirectly via the transport facilities 112 if the access point 14 isa personal Wi-Fi network or Wi-Fi hotspot (in which case a mechanism forsecurely connecting to the wireless connector system 120, such as avirtual private network (VPN), may be appropriate). The AP interface 116provides translation and routing services between the access points 114and the wireless connector system 120 to facilitate communication,directly or indirectly, with the wireless connector system 120.

The wireless connector system 120 may be implemented as one or moreservers, and is typically located behind a firewall 113. The wirelessconnector system 120 manages communications, including email messages,to and from a set of managed mobile communication devices 201. Thewireless connector system 120 also provides administrative control andmanagement capabilities over users and mobile communication devices 201which may connect to the wireless connector system 120.

The wireless connector system 120 allows the mobile communicationdevices 201 to access the network 124 and connected resources andservices such as a messaging server 132 (for example, a MicrosoftExchange™, IBM Lotus Domino™, or Novell GroupWise™ email messagingserver) having a global address book 134, and optionally other servers142. The other servers 142 may comprise a content server for providingcontent such as internet content or content from an organization'sinternal servers to the mobile communication devices 201 in the wirelessnetwork 101, and an application server for implementing server-basedapplications.

The global address book 134 comprises electronic contact recordsgenerated and maintained by an IT (information technology) administratorof the network 124. Typically, the global address book is maintainedexclusively by the messaging server 132 and there is no local copy onthe mobile device 201. In addition, the global address book typicallycomprises contact records for all users of the respective network 124(e.g., enterprise). The contact records in the global address book 134may be one or more of individual contact records (or user records) or agroup address or distribution list which lists multiple individual(users).

The wireless connector system 120 typically provides a secure exchangeof data (e.g., email messages, personal information manager (PIM) data,and IM data) with the mobile communication devices 201. In someembodiments, communications between the wireless connector system 120and the mobile communication devices 201 are encrypted. In someembodiments, communications are encrypted using a symmetric encryptionkey implemented using Advanced Encryption Standard (AES) or Triple DataEncryption Standard (Triple DES) encryption. Private encryption keys aregenerated in a secure, two-way authenticated environment and are usedfor both encryption and decryption of data.

The wireless network gateway 110 is adapted to send data packetsreceived from the mobile device 201 over the WWAN 102 to the wirelessconnector system 120. The wireless connector system 120 then sends thedata packets to the appropriate connection point such as the messagingserver 132, content server 132 or application servers 136. Conversely,the wireless connector system 120 sends data packets received, forexample, from the messaging server 132 or other server 142 to thewireless network gateway 110 which then transmit the data packets to thedestination mobile device 201. The AP interfaces 116 of the WLAN 104provide similar sending functions between the mobile device 201, thewireless connector system 120 and network connection point such as themessaging server 132, content server 132 and application server 136.

The network 124 may comprise a private local area network, metropolitanarea network, wide area network, the public internet or combinationsthereof and may include virtual networks constructed using any of these,alone, or in combination. Computers 117 may be connected to the network124 directly or indirectly via an intermediate communication networksuch as the Internet 112. When computers 117 connect to the networkindirectly, e.g. via the Internet 112, a VPN or other mechanism forsecurely connecting to the network 124 may be appropriate. Computers 117may be of any suitable construction and include at least a processor,and a display screen, one or more user input devices, and a memory eachconnected to the processor as is known in the art. The computers 117could be desktop computers, laptop/notebook/netbook computers, orcombinations thereof, and may have wired or wireless communicationsubsystems for connecting to the network 124.

A mobile device 201 may alternatively connect to the wireless connectorsystem 120 using a computer 117 via the network 124. In at least someembodiments, for security purposes the computers 117 with which themobile devices 201 can connect to the wireless connector system 120 arelimited to computers 117 which are directly connected to the network124. A link 106 may be provided for exchanging information between themobile device 201 and computer 117 connected to the wireless connectorsystem 120. The link 106 may comprise one or both of a physicalinterface and short-range wireless communication interface. The physicalinterface may comprise one or combinations of an Ethernet connection,Universal Serial Bus (USB) connection, Firewire™ (also known as an IEEE1394 interface) connection, or other serial data connection, viarespective ports or interfaces of the mobile device 201 and computer117. The short-range wireless communication interface may be a personalarea network (PAN) interface. A personal area network is a wirelesspoint-to-point connection meaning no physical cables are required toconnect the two end points.

It will be appreciated that the above-described communication system isprovided for the purpose of illustration only, and that theabove-described communication system comprises one possiblecommunication network configuration of a multitude of possibleconfigurations for use with the mobile communication devices 201. Theteachings of the present disclosure may be employed in connection withany other type of network and associated devices that are effective inimplementing or facilitating wireless communication. Suitable variationsof the communication system will be understood to a person of skill inthe art and are intended to fall within the scope of the presentdisclosure.

Reference is now made to FIG. 2 which illustrates an exemplaryembodiment of the mobile device 201 in which example embodimentsdescribed in the present disclosure can be applied. The mobile device201 is a two-way communication device having data and voicecommunication capabilities, and the capability to communicate with othercomputer systems, for example, via the Internet. Depending on thefunctionality provided by the mobile device 201, in various embodimentsthe device 201 may be a multiple-mode communication device configuredfor both data and voice communication, a smartphone, a mobile telephoneor a PDA (personal digital assistant) enabled for wirelesscommunication, or a computer system with a wireless modem.

The mobile device 201 includes a rigid case (not shown) housing thecomponents of the device 201. The internal components of the device 201are constructed on a printed circuit board (PCB). The mobile device 201includes a controller comprising at least one processor 240 (such as amicroprocessor) which controls the overall operation of the device 201.The processor 240 interacts with device subsystems such as a wirelesscommunication subsystem 211 (sometimes referred to as a radio layer) forexchanging radio frequency signals with the wireless network 101 toperform communication functions. The processor 240 interacts withadditional device subsystems including a display screen 204 such as aliquid crystal display (LCD) screen, input devices 206 such as akeyboard and control buttons, flash memory 244, random access memory(RAM) 246, read only memory (ROM) 248, auxiliary input/output (I/O)subsystems 250, data port 252 such as serial data port, such as aUniversal Serial Bus (USB) data port, speaker 256, microphone 258,short-range communication subsystem 262, and other device subsystemsgenerally designated as 264. Some of the subsystems shown in FIG. 2perform communication-related functions, whereas other subsystems mayprovide “resident” or on-device functions.

The device 201 may comprise a touch screen display in some embodiments.The touch screen display may be constructed using a touch-sensitiveinput surface connected to an electronic controller and which overlaysthe display screen 204. The touch-sensitive overlay and the electroniccontroller provide a touch-sensitive input device and the processor 240interacts with the touch-sensitive overlay via the electroniccontroller. In some embodiments, a touch screen is integrated directlywith the display. In still other embodiments, a touch screen is placedbehind the display.

The communication subsystem 211 includes a receiver 214, a transmitter216, and associated components, such as one or more antenna elements 218and 220, local oscillators (LOs) 222, and a processing module such as adigital signal processor (DSP) 224. The antenna elements 218 and 220 maybe embedded or internal to the mobile device 201 and a single antennamay be shared by both receiver and transmitter, as is known in the art.As will be apparent to those skilled in the field of communication, theparticular design of the wireless communication subsystem 211 depends onthe wireless network 101 in which mobile device 201 is intended tooperate.

The mobile device 201 may communicate with any one of a plurality offixed transceiver base stations 108 of the wireless network 101 withinits geographic coverage area. The mobile device 201 may send and receivecommunication signals over the wireless network 101 after the requirednetwork registration or activation procedures have been completed.Signals received by the antenna 218 through the wireless network 101 areinput to the receiver 214, which may perform such common receiverfunctions as signal amplification, frequency down conversion, filtering,channel selection, etc., as well as analog-to-digital (A/D) conversion.A/D conversion of a received signal allows more complex communicationfunctions such as demodulation and decoding to be performed in the DSP224. In a similar manner, signals to be transmitted are processed,including modulation and encoding, for example, by the DSP 224. TheseDSP-processed signals are output to the transmitter 216 fordigital-to-analog (D/A) conversion, frequency up conversion, filtering,amplification, and transmission to the wireless network 101 via theantenna 220. The DSP 224 not only processes communication signals, butmay also provide for receiver and transmitter control. For example, thegains applied to communication signals in the receiver 214 and thetransmitter 216 may be adaptively controlled through automatic gaincontrol algorithms implemented in the DSP 224.

The processor 240 operates under stored program control and executessoftware modules 221 stored in memory such as persistent memory, forexample, in the flash memory 244. As illustrated in FIG. 2, the softwaremodules 221 comprise operating system software 223, softwareapplications 225 comprising an email messaging application 272 (alsoreferred to as an email client 272), a personal address book 274, acalendar application 276, a phone application 278, and graphicalauthentication module 280. Example embodiments of the graphicalauthentication module 280 will be discussed in detail later herein. Itis recognized that the graphical authentication module 280 and itsvarious components as described herein can form a discrete modulerunning on the device 201, or the functions of the graphicalauthentication module 280 can be distributed on the device 201 asseparate modules or integrated within other existing modules as desired.Such discrete or distributed implementations all fall within theembodiments of the graphical authentication module 280 as describedherein.

The software applications 225 also may include a range of applications,including, for example, a notepad application, Internet browserapplication, voice communication (i.e. telephony) application, mappingapplication, or a media player application, or any combination thereof.Each of the software applications 225 may include layout informationdefining the placement of particular fields and graphic elements (e.g.text fields, input fields, icons, etc.) in the user interface (i.e. thedisplay screen 204) according to the application.

Those skilled in the art will appreciate that the software modules 221or parts thereof may be temporarily loaded into volatile memory such asthe RAM 246. The RAM 246 is used for storing runtime data variables andother types of data or information, as will be apparent to those skilledin the art. Although specific functions are described for various typesof memory, this is merely one example, and those skilled in the art willappreciate that a different assignment of functions to types of memorycould also be used.

In some embodiments, the auxiliary I/O subsystems 250 may comprise anexternal communication link or interface, for example, an Ethernetconnection. The mobile device 201 may comprise other wirelesscommunication interfaces for communicating with other types of wirelessnetworks, for example, a wireless network such as an orthogonalfrequency division multiplexed (OFDM) network or a GPS (GlobalPositioning System) subsystem comprising a GPS receiver or transceiverfor communicating with a GPS satellite network (not shown). Theauxiliary I/O subsystems 250 may comprise a pointing or navigationalinput device such as a touchpad, a clickable trackball or scroll wheelor thumbwheel, or a vibrator for providing vibratory notifications inresponse to various events on the device 201 such as receipt of anelectronic message or incoming phone call, or for other purposes such ashaptic feedback (touch feedback).

In some embodiments, the mobile device 201 also includes a removablememory card or module 230 (typically comprising flash memory) and amemory card interface 232. Network access is typically associated with asubscriber or user of the mobile device 201 via the memory card 230,which may be a Subscriber Identity Module (SIM) card for use in a GSMnetwork or other type of memory card for use in the relevant wirelessnetwork type. The memory card 230 is inserted in or connected to thememory card interface 232 of the mobile device 201 in order to operatein conjunction with the wireless network 101.

The mobile device 201 also stores other data 227 in an erasablepersistent memory, which in one example embodiment is the flash memory244. In various embodiments, the data 227 includes service datacomprising information required by the mobile device 201 to establishand maintain communication with the wireless network 101. The data 227may also include user application data such as email messages, addressbook and contact information, calendar and schedule information, notepaddocuments, image files, and other commonly stored user informationstored on the mobile device 201 by its user, and other data. The data227 stored in the persistent memory (e.g. flash memory 244) of themobile device 201 may be organized, at least partially, into a number ofdatabases each containing data items of the same data type or associatedwith the same application. For example, email messages, contact records,and task items may be stored in individual databases within the devicememory.

The mobile device 201 also includes a battery 238 as a power source,which is typically one or more rechargeable batteries that may becharged, for example, through charging circuitry coupled to a batteryinterface such as the serial data port 252. The battery 238 provideselectrical power to at least some of the electrical circuitry in themobile device 201, and the battery interface 236 provides a mechanicaland electrical connection for the battery 238. The battery interface 236is coupled to a regulator (not shown) which provides power V+ to thecircuitry of the mobile device 201.

The short-range communication subsystem 262 is an additional optionalcomponent which provides for communication between the mobile device 201and different systems or devices, which need not necessarily be similardevices. For example, the subsystem 262 may include an infrared deviceand associated circuits and components, or a wireless bus protocolcompliant communication mechanism such as a Bluetooth® communicationmodule to provide for communication with similarly-enabled systems anddevices.

A predetermined set of applications that control basic deviceoperations, including data and voice communication applications willnormally be installed on the mobile device 201 during or aftermanufacture. Additional applications and/or upgrades to the operatingsystem 221 or software applications 225 may also be loaded onto themobile device 201 through the wireless network 101, the auxiliary I/Osubsystem 250, the serial port 252, the short-range communicationsubsystem 262, or other suitable subsystem 264. The downloaded programsor code modules may be permanently installed, for example, written intothe program memory (i.e. the flash memory 244), or written into andexecuted from the RAM 246 for execution by the processor 240 at runtime.Such flexibility in application installation increases the functionalityof the mobile device 201 and may provide enhanced on-device functions,communication-related functions, or both. For example, securecommunication applications may enable electronic commerce functions andother such financial transactions to be performed using the mobiledevice 201.

The mobile device 201 may provide two principal modes of communication:a data communication mode and a voice communication mode. In the datacommunication mode, a received data signal such as a text message, anemail message, or Web page download will be processed by thecommunication subsystem 211 and input to the processor 240 for furtherprocessing. For example, a downloaded Web page may be further processedby a browser application or an email message may be processed by theemail messaging application and output to the display 204. A user of themobile device 201 may also compose data items, such as email messages,for example, using the input devices in conjunction with the displayscreen 204. These composed items may be transmitted through thecommunication subsystem 211 over the wireless network 101.

In the voice communication mode, the mobile device 201 providestelephony functions and operates as a typical cellular phone. Theoverall operation is similar, except that the received signals areoutput to the speaker 256 and signals for transmission are generated bya transducer such as the microphone 258. The telephony functions areprovided by a combination of software/firmware (i.e., the phoneapplication 278) and hardware (i.e., the microphone 258, the speaker 256and input devices). Alternative voice or audio I/O subsystems, such as avoice message recording subsystem, may also be implemented on the mobiledevice 201. Although voice or audio signal output is typicallyaccomplished primarily through the speaker 256, the display screen 204may also be used to provide an indication of the identity of a callingparty, duration of a voice call, or other voice call relatedinformation.

The phone application 278 can be split into multiple applications orsub-modules, for example one or more user phone modules and a callcontrol module. The user phone modules provide a variety of telephonyfeatures through a user interface, while the call control moduleprovides access to common telephony functions desired by the user phonemodules, such that telephony requests from phone modules can becoordinated and so that the user phone modules do not need to eachprovide instructions understood by the wireless communications subsystem211. The call control function typically makes telephony featuresavailable to user phone modules through an application programminginterface (API). It is to be recognized that all or part of the phoneapplication 278 features or functions could be provided through theoperating system or otherwise distributed in the device 201, whilecontinuing to fall within the term phone application 278.

Referring now to FIG. 3, an exemplary computer readable media 310 willbe described. The computer readable media 310 have computer readableinstructions 320 stored thereon that when implemented cause a processor330 to execute any one of the methods described herein. For the purposesof the application, computer readable media comprise any tangiblecomputer storage, such as but not limited to flash memory, read onlymemory, CD, DVD, and memory sticks. Graphical authentication module 280described above with reference to FIG. 2 is an exemplary implementationof computer readable media 310. However, it is to be understood that thecomputer readable media 310 is not limited to use on mobile devices,such as mobile device 210 described above. Non-limiting examples of theprocessor 330 include a CPU (central processing unit) on a personalcomputer, laptop computer, tablet device, personal digital assistant(PDA), mobile telephone, smart phone, bank machine, and digitalauthentication system for entry to rooms or buildings, or controlsystem. Any device with a processor, a display and a user interfaceenabling a user to move images on the display could feasibly make use ofthe computer readable media 310 to authenticate users.

A flow chart of a method that can be implemented by the processor 330 isshown in FIG. 4 a. The method is a method of authenticating a user of acomputing device, the computing device having a memory storing a baseimage and an overlay image, the base image having a pre-selected baseimage reference point, and the overlay image having a pre-selectedoverlay image reference point. The method starts with generating 410 amodified base image and generating 420 a modified overlay image. Then,the method continues with displaying 430, on a touch screen display, themodified base image overlaid by the modified overlay image. Action 440of the method is receiving an input for moving one of the modified baseimage and the modified overlay image. Then the method continues withmoving 450 the one of the modified base image and the modified overlayimage if a criterion for movement of the one of the modified base imageand the modified overlay image is met. Finally, in response to alignmentof the base image reference point on the modified base image with theoverlay image reference point on the modified overlay image at a pointon the touch screen after the moving, the method ends with indicating460 positive authentication. Non-limiting examples of indicatingpositive authentication include: providing a visual indicator; providingan audible indicator; and allowing user access.

Referring now to FIG. 4 b, another example method will be described. Themethod in FIG. 4 b starts with actions 410, 420 and 430 from FIG. 4 a.At action 435, the method differs slightly. An input to move at leastone of the modified base image and the modified overlay image isreceived. Then a determination 436 of whether a criterion for moving hasbeen met. If the criterion is met, the image is moved 450. Then, afterthe moving, a determination 455 is made of whether or not the base imagereference point and the overlay image reference point are aligned. Ifthe determination is that there is alignment, the method proceed toaction 460 which the same as action 460 in FIG. 4 a, that is indicatingpositive authentication. If there is no alignment or if the criterionfor movement is not met, the method proceeds to indicating 470 thatauthentication failed.

The indication that authentication failed in some embodiments is anaudio signal. In some embodiments, the indication that authenticationfailed is a visual output on the display. In some embodiments, ifauthentication failed, the method starts over. In some embodiments,after a set number of failed authentication attempts, a user is lockedout and not permitted to attempt authentication again. In someembodiments, the user is locked out until an administrator overrides thelock out. In other embodiments, the lock out is for a set time period.

In some embodiments the method further comprises timing theauthentication attempt. If positive authentication is not indicatedwithin a time limit, the method proceeds to action 460, i.e. indicatingthat authentication failed.

In an alternate embodiment, when the overlay image is moved, themodified base image disappears. In other words, the moving comprisesmoving the overlay image and the method further comprises removing themodified base image from the display in response to receiving the input.Therefore, the user must remember where the base image reference pointwas located on the display and align the overlay image reference pointwithout being able to see it. This adds security in that a third partycan not see any two points being aligned. However, tolerances foralignment would likely be less strict than in the case where the usercan see the base image reference point.

In some embodiments, the criterion for movement is that the input is atouch at a location other than the pre-selected overlay image referencepoint. In some embodiments, the criterion for movement is that the inputis a touch at a location other than the pre-selected base imagereference point. In some embodiments, the criterion for movement is thatthe input is a touch at a designated location on one of the modifiedbase image and the modified overlay image. In some embodiments, thecriterion for movement is that the input is a touch at a grid line onthe overlay image. In some embodiments, the criterion for movement isthat the input is a touch at a tab on the overlay image. In someembodiments, the criterion for movement is that the input is a vectorstroke having a length less than a maximum length. In some embodiments,the vector stroke must be within a directional tolerance in order tomeet the criterion.

In some embodiments, the method further comprises randomly alteringwhether the overlay image or the base image moves in response to theinput. In other embodiments, the decision as to which image to move isnot random but rather is based on logic. In a non-limiting example, theoverlay image is moved unless the touch is in a vicinity of the overlayimage reference point.

In some embodiments, if the input is a touch on the pre-selected baseimage reference point, the system allows for the movement of the overlayimage and if the input is a touch on the pre-selected overlay imagereference point, the base image is moved.

In non-limiting exemplary embodiments, the base image is a photograph ofa scene and the pre-selected reference point is an object in the scene.In other non-limiting embodiments, the base image includes a pluralityof abstract objects and the pre-selected reference point is one of theabstract objects. In other embodiments, the base image is a grid ofnumbers, characters or objects.

In non-limiting embodiments, the overlay image is a grid of numbers,characters or objects. In some embodiments, the pre-selected number,character or object appears more than once in the grid. As with the baseimage, the overlay image in some embodiments is a photo or abstractimage. In some cases, when the image is overlaid on the base image, itis presented so that the base image, or portions thereof are visiblethrough the overlay image.

In some embodiments, one or both of the overlay image and the base imageis a 3-D image. In some embodiments, one or both of the overlay imageand the base image have data for three dimensions but are displayed on a2-D screen. Points in all three dimensions can be selected and movementwithin the three dimensions is possible in these embodiments. In someembodiments, the images are displayed on a 3-D screen.

In some embodiments, the reference point on either the base image oroverlay image or both is represented by a dot, an x or some other symbolnext to a recognizable part of the image, such as a number, character,or object. In some embodiments, the reference point is represented by anumber, character or object in the respective image. In someembodiments, aligning the reference points includes bringing one of thereferences points within a predefined distance of the other referencepoint. In other words, there may be a tolerance zone. An example of atolerance zone is an area around a reference point in which a userselection will be interpreted as selection of the reference point. Thetolerance zone can be made smaller for increased security or largerwhere less precision is possible. In some embodiments, the tolerancezone is variable and is made smaller when increased security isrequired.

In some embodiments, one or both of the overlay image and the base imagestored in the memory comprise data or instructions for generating therespective image. For example, the stored image can compriseinstructions to generate a 2D grid of numbers from 1 to 100.

While the methods described with reference to FIGS. 4 a and 4 b refer toone base image and one overlay image and a single reference point oneach image, it is to be understood that any number of images andreference points can be used. It is to be understood that the methodsdescribed herein are not limited to the order in which the actions arepresented herein and that the various actions may be implemented in adifferent order in other embodiments.

In some example embodiments, the computer readable media 310 is locatedon the computing device. FIG. 5 shows a computing device 500 withcomputer readable media 310 installed thereon. The computing device 500also comprises a memory 510 on which the base image 511 and the overlayimage 521 are stored. Non-limiting examples of formats for storing thebase image 511 and the overlay image 521 are bitmap, PDF, JPEG, and PNG.In some embodiments, for example where a grid is used, the format of theimage can include different fonts or font technologies. In someembodiments, the memory 510 is an external memory, such as a memorystick or a memory on a server. A display 530 is also provided fordisplaying representations or modified versions of the base image 511and the overlay image 521. In some embodiments, the display is atouchscreen.

In some embodiments of the computer readable media 310, generating themodified base image comprises randomly altering the position of the baseimage reference point on the display. In some embodiments, the baseimage reference point is altered with respect to the rest of the baseimage. In other embodiments, generating the modified overlay imagecomprises randomly altering the position of the overlay image referencepoint. In some embodiments, both the base image reference point and theoverlay image reference point positions are altered.

In some embodiments, one or both of the overlay image and the base imageare distorted. Examples of distorting the image include but are notlimited to stretching the image (rubber band effect), blurring portionsof the image, compressing the image and morphing the image. Anotherexample involves generating a collage of images from the base image oroverlay image, where the collage can be reconfigured. In such anembodiment, in presenting the collage or modified image, the respectivereference points should be visible and not overlapped. In someembodiments, if the reference point is a number or character, the fontcan be changed.

In some embodiments, generating the modified base image comprises makinga copy of the base image. In some embodiments, the copy is an exactcopy. Likewise, in some embodiments, generating the modified overlayimage comprises making a copy of the overlay image and the copy of theoverlay image, in some cases, can be an exact copy of the overlay image.

Non-limiting examples of presenting the modified images includepresenting the respective image at a different location each time theinstructions are executed, distorting the appearance of the image androtating the modified image.

In some embodiments of the computer readable media 310, the inputcomprises a movement of the modified base image and a movement of themodified overlay image. The modified images are moved by the user usingnavigation controls on the computing device in some embodiments. Forexample, a mouse can be used to click and drag the image to be moved. Ifa touch screen is used, the user can touch and drag one or both images.Other non-limiting navigation controls include keys on a keyboard, atouchpad, a trackball, a thumbwheel and a joystick. In an exemplaryembodiment, the input comprises a sequence of movements of the baseimage and the overlay image. In some embodiments, the representations ofthe images must be moved in a specific sequence. For example, first moveone of the modified base image and the modified overlay image and thenmove the other of the two so that the respective reference points arealigned. In an exemplary embodiment, individual touch is used to moveboth planes, i.e. the base image plane and the overlay image plane. Insome embodiments, each plane can be moved simultaneously by a differentfinger if multi-touch input is supported. Some embodiments restrict themovement of each representation in horizontal, diagonal or verticaldirections.

In some embodiments, gestures are used to move the modified base imageor the modified overlay image or both. For example, pressure or anaccelerometer can control the movement.

Screen wrap can also be used in some embodiments to confuse third partyobservers. Screen wrap can be used in at least two manners. In thefirst, when part of the image moves off one edge of the display, thatpart appears immediately on the opposite side. In the first manner, theimage is usually the same size as the display. In the second manner,which is sometimes used when the image is larger than the display, partof the image moves off the edge but is not seen immediately on theopposite side. In this case, the third party observer would not see theentire image. In some such embodiments, one or more of the referencepoints may not be visible on the screen at first and the user has tomove the representation of the respective image to bring the referencepoint into view.

In some embodiments, the overlay image is split on the display dependingon where the user touches the display. For example, if the user touchesthe display very close to the right edge of the display, part of theoverlay image may appear on the right side of the display with theremainder appearing on the left side of the display.

In one embodiment, the overlay image is a grid of numbers and when themodified overlay image is displayed, the grid could move up or down withonly a portion of the grid visible, i.e. higher or lower numbers may notbe visible. The user moves the grid to align the pre-selected numberwith the reference point on the modified base image. In someembodiments, the pre-selected number must be moved up or down to theproper height and then moved left or right to align with the referencepoint on the base image. The requirement to move a reference pointvertically and then horizontally or vice versa can be used in anyembodiment and is not limited to a grid of numbers.

Panoramic photos can also be used for either the base image or theoverlay image or both. In some such embodiments, the photo is moveableto align the reference points. In some embodiments, the photo ismoveable to align a point on the photo with a number on a grid. In someembodiments, the photo is moveable to align a point on the photo with acolumn and row in a grid corresponding to a pre-selected number. Inother embodiments, the photo is moveable left or right only. In otherembodiments, the photo is moveable up and down only.

In some embodiments, the overlay image is a grid of images andpresenting the modified overlay image comprises altering the position ofthe pre-selected overlay image reference point while maintaining atleast one of a column and a row with images having a commoncharacteristic. In an exemplary embodiment, the grid is a grid ofnumbers with all of the “x1s” in one column (1, 11, 21, etc.) and all ofthe “x2s” in another column (2, 12, 22, etc) and so on, but the positionof each number with the respective column changes each time theinstructions are executed. For example, if the grid is a grid of numbersand the pre-selected reference point on the overlay image is the number23, each time the grid is presented the reference point will be in adifferent row and column, but always in the same column as the “20s” andthe same row as the “x3s”. If the grid consists of shapes of varyingsizes, colours or other features, a feature (square shape, for example)could always be in the same column but the position in the column couldchange. Maintaining the reference point in a column or row with pointsof a common characteristic provides some assistance to the user infinding the reference point while maintaining the added security ofrandomly altering the location of the reference point.

In still another embodiment, the grid is randomly generated in responseto a user input, such as, but not limited to, a gesture, selecting akey, and a sequence of keystrokes. For example, with a device with anaccelerometer, shaking could reset the grid. In another example, thegrid could reset upon each touch on the display. In some embodiments,the grid does not appear until the display is touched. In otherembodiments, upon touch, the grid disappears and then re-appears withthe objects in the grid in a different order. In other embodiments, themodified base image or the modified overlay image or both could beprogrammed to reset after a predetermined period of time.

In some embodiments, there are two pre-selected overlay image referencepoints. To authenticate, the user must move a first overlay imagereference point to align with a first base image reference point andthen move the base image to align a second base image reference pointwith a second overlay image reference point. In embodiments, the firstand second base image reference points are the same.

Referring to FIG. 6, a computing device 600 will be described. In someembodiments the computing device 600 is a mobile communications devicesuch as the mobile device 201 described herein. However, it is to beunderstood that the computing device 600 can be any computing device.Non-limiting examples include a personal computer, laptop computer,tablet device, personal digital assistant (PDA), mobile telephone, smartphone, bank machine, an access device for allowing access to a buildingor room, and an electronic controller for controlling systems orequipment.

The computing device 600 comprises the graphical computer readable media310, a touchscreen 620, and a processor 630. The touchscreen 620 is usedto display the modified base image and the modified overlay image and toreceive the input for moving the modified base image or the modifiedoverlay image. The processor 630 for executing the instructions. In someembodiments, the computing device 600 also comprises the memory. Thecomputing device 600, in some embodiments also comprises a flash memoryon which the authentication module is located.

In some embodiments, dedicated controls are provided on the computingdevice 600 for moving the representations of the base image or theoverlay image or both.

It is to be understood that the embodiments described herein are notlimited to one base image and one overlay image. Multiple layers ofimages are possible. Furthermore, multiple reference points on eachlayer are also possible.

Referring now to the screens shots of FIGS. 7 a to 7 d, a specificimplementation of a proposed method will be described. FIG. 7 a shows abase image 700, including a number of objects that can be selected as areference point: a tree, a flower, a person, a bird, a sun, and a cloud.In this example, the user has selected the flower 710 as the base imagereference point. In FIG. 7 b, an overlay image 720 which is a grid ofnumbers from 1 to 12 is shown. In this case, the user has selectednumber 8 as the overlay image reference point 722. In other embodiments,the grid need not be presented to the user to do the selection. Adialogue box can be presented asking the user to select a numberbetween, for example, 1 and 12. Referring to FIG. 7 c, to start theauthentication of the user, a modified base image 730 is presentedoverlaid with a modified overlay image 740. In modified base image 730,the position of the flower 710 has been altered. In some embodiments,the position of the base image reference point 710 varies with eachauthentication attempt. In modified overlay image 740, the order of thenumbers in the grid has been altered, so that the overlay referencepoint 722 is in a different position. It is to be understood that insome embodiments, the order of the numbers in the grid remains the sameand that the position of the overlay image reference point 722 mayremain the same while the position of the base image reference point 710varies. In some embodiments, the numbers can appear more than once inthe modified overlay image. Referring to FIG. 7 d, the user hassuccessfully completed the authentication by meeting the criterion formovement and moving the modified overlay image 740 so that the overlayimage reference point 722 is aligned with the base image reference point710.

While the present disclosure is sometimes described in terms of methods,a person of ordinary skill in the art will understand that the presentdisclosure is also directed to various apparatus including componentsfor performing at least some of the aspects and features of thedescribed methods, be it by way of hardware components, software or anycombination of the two, or in any other manner. Moreover, an article ofmanufacture for use with the apparatus, such as a pre-recorded storagedevice or other similar computer readable medium including programinstructions recorded thereon may direct an apparatus to facilitate thepractice of the described methods. It is understood that such apparatus,articles of manufacture also come within the scope of the presentdisclosure.

The various embodiments presented above are merely examples and are inno way meant to limit the scope of this disclosure. Variations of theinnovations described herein will be apparent to persons of ordinaryskill in the art, such variations being within the intended scope of thepresent application. In particular, features from one or more of theabove-described embodiments may be selected to generate alternativeembodiments comprised of a sub-combination of features which may not beexplicitly described above. In addition, features from one or more ofthe above-described embodiments may be selected and combined to generatealternative embodiments comprised of a combination of features which maynot be explicitly described above. Features suitable for suchcombinations and sub-combinations would be readily apparent to personsskilled in the art upon review of the present application as a whole.The subject matter described herein and in the recited claims intends tocover and embrace all suitable changes in technology.

1. One or more computer readable media having computer readableinstructions stored thereon that when executed by a processor implementa method of authenticating a user of a computing device, the computingdevice having a memory storing a base image and an overlay image, thebase image having a pre-selected base image reference point, and theoverlay image having a pre-selected overlay image reference point, themethod comprising: generating a modified base image; generating amodified overlay image; displaying, on a display, the modified baseimage overlaid by the modified overlay image; receiving an input formoving one of the modified base image and the modified overlay image;moving the one of the modified base image and the modified overlay imageif a criterion for movement of the one of the modified base image andthe modified overlay image is met; and in response to alignment of thebase image reference point on the modified base image with the overlayimage reference point on the modified overlay image at a point on thedisplay after the moving, indicating positive authentication.
 2. Thecomputer readable media of claim 1, wherein the criterion for movementis that the input is a touch at a location other than the pre-selectedoverlay image reference point.
 3. The computer readable media of claim1, wherein the criterion for movement is that the input is a touch at alocation other than the pre-selected base image reference point.
 4. Thecomputer readable media of claim 1, wherein the criterion for movementis that the input is a touch at a designated location on one of themodified base image and the modified overlay image.
 5. The computerreadable media of claim 1, wherein the criterion for movement is thatthe input is a touch at a grid line on the overlay image.
 6. Thecomputer readable media of claim 1, wherein the criterion for movementis that the input is a touch at a tab on the overlay image.
 7. Thecomputer readable media of claim 1, wherein the criterion for movementis that the input is a vector stroke having a length less than a maximumlength.
 8. The computer readable media of claim 7, wherein the vectorstroke must be within a directional tolerance in order to meet thecriterion.
 9. The computer readable media of claim 1, wherein the methodfurther comprises randomly altering whether the overlay image or thebase image moves in response to the input.
 10. A method ofauthenticating a user of a computing device, the computing device havinga memory storing a base image and an overlay image, the base imagehaving a pre-selected base image reference point, and the overlay imagehaving a pre-selected overlay image reference point, the methodcomprising: generating a modified base image; generating a modifiedoverlay image; displaying, on a display, the modified base imageoverlaid by the modified overlay image; receiving an input for movingone of the modified base image and the modified overlay image; movingthe one of the modified base image and the modified overlay image if acriterion for movement of the one of the modified base image and themodified overlay image is met; and in response to alignment of the baseimage reference point on the modified base image with the overlay imagereference point on the modified overlay image at a point on the displayafter the moving, indicating positive authentication.
 11. The method ofclaim 10, further comprising randomly altering whether the overlay imageor the base image moves in response to the input.
 12. The method ofclaim 10, further comprising: if the input is a touch on thepre-selected base image reference point, moving the overlay image; andif the input is a touch on the pre-selected overlay image referencepoint, moving the base image.
 13. The method of claim 10, wherein thecriterion for movement is that the input is a touch at a location otherthan the pre-selected overlay image reference point.
 14. The method ofclaim 10, wherein the criterion for movement is that the input is atouch at a location other than the pre-selected base image referencepoint.
 15. The method of claim 10, wherein the criterion for movement isthat the input is a touch at a designated location on one of themodified base image and the modified overlay image.
 16. The method ofclaim 10, wherein the criterion for movement is that the input is avector stroke having a length less than a maximum length.
 17. Acomputing device comprising: a processor; a display; and one or morecomputer readable media having computer readable instructions storedthereon that when executed by the processor implement a method ofauthenticating a user of the computing device, the computing devicehaving a memory storing a base image and an overlay image, the baseimage having a pre-selected base image reference point, and the overlayimage having a pre-selected overlay image reference point, the methodincluding generating a modified base image; generating a modifiedoverlay image; displaying, on the display, the modified base imageoverlaid by the modified overlay image; receiving an input for movingone of the modified base image and the modified overlay image; movingthe one of the modified base image and the modified overlay image if acriterion for movement of the one of the modified base image and themodified overlay image is met; and in response to alignment of the baseimage reference point on the modified base image with the overlay imagereference point on the modified overlay image at a point on the touchscreen after the moving, indicating positive authentication.
 18. Thecomputing device of claim 14, further comprising the memory.
 19. Thecomputing device of claim 14, wherein the display is a touchscreen. 20.The computing device of claim 14, comprising a mobile electronic device.